For example, various systems configured to obtain power from power generators such as solar cells and fuel cells are known. One example of the systems is a centralized control system configured to integrally control a plurality of solar panels by a power conditioner. In a centralized control system, all the direct current (DC) power generated by a plurality of solar panels is collectively converted into alternating direct (AC) power by a single power conditioner.
These days, a new system such as a decentralized control system has been gathering attention as an alternative to the above-described centralized control system. In a decentralized control system, inverters are connected respectively to a plurality of solar panels. The inverters convert DC power into AC power individually for the respective solar panels.
Further, in the decentralized control system, there is demand for a technique to perform power generation control or monitoring of each solar panel using wireless communication. In response to the demand for the technique, a method of, for example, providing an inverter with a wireless communication module has been proposed. In this method, a wireless communication module is accommodated in a housing together with an inverter circuit.
In this case, the housing needs to be made of a metal material to maintain a certain strength (rigidity) for the entire housing. In a wireless communication module, a portion effective as an antenna (antenna portion) is required to achieve high antenna performance or wireless communication performance. Note that the antenna performance is degraded when the antenna portion approaches the housing (metal). The wireless communication performance is degraded when the antenna portion is influenced by noises produced by the inverter.